Synchronization Priority / Very high respone time in clients

[rweise]

Hello,
I have a Windows Cluster with 2 nodes und about 15 HyperV-VMs, that are all using storage on Starwind VSAN. Network between the nodes is 10GB. The VSAN is build with one NVME of each node. My problem is, das the response times of the disks in the VMs are very bad, often more than 300ms. The NVME-disks and the network are ok, I tested it without Starwind VSAN. Has anyone a hint for me what to do? Maybe I should use the "Change synchronization priority"-Switch in Starwind. It ist now on the left side (faster synchronization) and my idea is to switch it far on the right side (faster client request processing). But I don't find any further documention about the impacts. Also there is no real traffic on the 10GB-Connection, so I am unsure if it is a good idea. What else could be the reason and how can I fix that? Thanks in advance.
Greetings,
Raphael

[yaroslav (staff)]

Greetings,
Can I learn more about network configuration? Are you using a dedicated direct physical link for iSCSI and Synchronization? Can I have the logs from you, please? Please use this tool: https://knowledgebase.starwindsoftware. ... collector/ and share the logs via Google Drive, Sharepoint, etc.
How did you measure the performance? was the production on? Please see this guide on StarWind Performance benchmarking https://www.starwindsoftware.com/best-p ... practices/. Are you using a free or Trial version of StarWind VSAN?

[kanecharles]

Greetings,
Can I learn more about network configuration? Are you using a dedicated direct physical link for iSCSI and Synchronization? Can I have the logs from you, please? Please use this tool: https://knowledgebase.starwindsoftware. ... collector/ and share the logs via Google Drive, Sharepoint, etc.
How did you measure the performance? was the production on? Please see this guide on StarWind Performance benchmarking https://www.starwindsoftware.com/best-p ... practices/. Are you using a free or Trial version of StarWind VSAN?

Disk response time problems in virtual machines can have many causes. First of all, you can try adjusting the sync priority in Starwind. However, before changing, consider carefully because there is no clear documentation on the impact of this. Also, check to see if there are any other causes of the problem and how to fix them, such as checking the network and drive configuration. Good luck!

[yaroslav (staff)]

Hi,

Sync priority can impact storage response times during Full or Fast sync only.
Speaking of the documents, the slider of synchronization priority in GUI is pretty much straightforward and self-explanatory: slide to the right to decrease sync priority and let more IO to the VMs and to the left for oposite. See more https://www.starwindsoftware.com/help/C ... ority.html